I thought one can extend this to cause error messages in $! (in Perl), e.g. "No such file or directory" and use single chars from them to try and form an obfuscated string. e.g. perl -e 'open(IN, "<", "");print @{[split(//,$!)]}[8,1,1,10,9,3,6];'

Have I re-invented the wheel or is this my first obfuscated Perl signature?